Optical properties and microstructures of TiO2thin film deposited on PMMA at low temperature
TiO2 thin films were deposited on low temperature on poly(methylmethacrylate)(PMMA)by DC pulse mag-netron sputtering.The effects of oxygen ratio,vacuum degree and other parameters on the structure and optical proper-ties of TiO2 thin films were studied.With the help of elliptic polarizing light tester,X-ray diffraction(XRD)tester,spec-trophotometer and atomic force microscope(AFM),the optical properties,element composition,crystallization proper ties and microstructure of the thin films were analyzed.The experimental result shows that with the increases of oxygen ratio,the deposition rate of the film decreases,the particle size of the film becomes larger,and the film tend to be looser.In term of optical properties,the refractive index deceases with the increase of oxygen proportion,but visible light trans-mittance increases,the reflectance appears redshift.The films packing densities calculated according to the refractive in-dex are 0.95,0.93,0.87,0.88 and 0.78 respectively,changes inversely with the proportion of oxygen.The band gap of the films calculated according to the spectrum is between 3.12～3.14 eV,changes inversely with the proportion of oxy-gen.With the decreases of vacuum,the deposition speed of the film first increased and then decreased.The films tend to be looser,and the refractive index decreased.The packing density of the film calculated according to the refractive index are 0.96,0.95,0.89,0.88,0.88,0.87,the vacuum degree has an positive effect on the visible light transmittance of the film,and has an negative effect on the band gap width of the film,which is between 3.13～3.16 eV,The TiO2 thin films deposited in this paper are amorphous,and the oxygen tatio and vacuum degree has little effect on their crystallinity.
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